Cache

I have two system running on two seperate JVM's and two seperate App Servers(both are weblogic 6.1),the important functionality is on both the system there is a cache program which holds data in HashMap but both are shairing the same database.. So for commuincating with both the cache or synchronize the cache as changes happen at any end should be reflected at another end, currently I am using http call to notify the change at one end so accordingly another program removes the old values and when next request comes it refreshes the data. This is all happening in current scenario.... This complete thing is in Java programs so now I want only one cache for both the servers which will share the same database. So Client want to use J2EE means ur EJB feature so what kind of bean is useful for this scenario..? On which server it needs to be deployed or will there be any server clustering? And how the notification process for synchronization of changes in database will happen...? Throw some ideas.....